once you change the domain name you no longer can control the email ids associated to old domain name
so easy way to delete them is
add the old domain name as parked domain and delete the mail ids then remove the old domain name from parked domains.
Flush dns, Clear browser cache and try again. I don't see any suspension on your account.
can you tell me your domain name or cpanel username you are trying.
***** Moved to programming help section ***************
Submit the form to some php file which will send the feedback to your mail. There are many feedback forms available on internet.
Remember to add captcha to feedback form to avoid spam.